In many manufacturing processes, such as semiconductor wafer processing, it is necessary to deliver very pure chemicals. The high purity of the chemicals is typically necessary to prevent contamination of the product by particles which can cause defects in the finished goods.
Semiconductor processing requires very pure chemicals delivered at almost every step of the processing. Impurities or particulates in the chemicals can have serious ramifications during processing; for example, a particle that is only 1/10 of a micron may be enough to cause a short-type defect in an integrated circuit developed on the wafer. Therefore, it is desirable to reduce and maintain particle contamination at the lowest possible level.
During the processing of semiconductor wafers, it is frequently necessary to rinse the wafers or otherwise apply a chemical. One method of applying the chemical or rinsing fluid to the wafers is to put them in a closed tank and deliver the fluid into a rotating dispenser. Frequently, the fluid source providing fluid to the rotating dispenser is stationary with respect to the dispenser and, thus, necessitates some type of rotating union. Unions developed for this purpose may have suffered from shortcomings such as contamination problems and wear problems.